The following type of pulse wave measuring device has been known. Specifically, the known pulse wave measuring device includes a portion (hereinafter referred to as a contact portion), against which a fingertip of a user contacts at the time of measuring the pulse wave, a light emitting element and a light receiving element. The light emitting element emits the light to the fingertip that contacts the contact portion. The light receiving element receives a reflected light, which is reflected from the fingertip, or a transmitted light, which is transmitted through the fingertip. The pulse wave measuring device measures the pulse wave based on an oscillatory change in the amount of light that is received through the light receiving element (see, for example, JPH07-213498A).
In order to accurately measure the pulse wave, the fingertip needs to contact the contact portion with an appropriate pressing force. In the case of the previously proposed pulse wave measuring device, it is difficult for the user to sense a location of the contact portion, and the fingertip sometimes deviates from the contact portion. Furthermore, in the case of the previously proposed pulse wave measuring device, the pressing force for pressing the fingertip against the contact portion sometimes becomes excessively large or excessively small.